Various types of aluminum-scandium alloys have been proposed. For example, U.S. Pat. No. 4,689,090 to Sawtell et al. discloses Al—Mg—Sc alloys which are said to possess improved superplastic forming properties.
U.S. Pat. No. 6,524,410 to Kramer et al. discloses 7XXX Al—Zn—Mg—Mn—Sc alloys useful as extruded bicycle tubing. However, welded structures fabricated from these alloys can be susceptible to stress corrosion cracking, which is a problem associated with many 7XXX alloys.
U.S. Pat. Nos. 5,597,529 and 5,620,652 to Tack et al. disclose aluminum-scandium alloys such as 7XXX Al—Zn—Mg—Mn—Cu—Sc alloys useful as recreational, athletic, aerospace, ground transportation and marine structures. These Cu-containing alloys suffer from susceptibility to general corrosion and may exhibit poor weldability in some cases.